How Dark Is The Film Edge Marking?

Hi All,

I have a general set of questions regarding the film edge markings (e.g. film code) that appear on B&W film. How dark should they appear? Are they supposed to be dark or light to medium in coloration? The reason for the question is that when I develop with T-Max developer, I get a light to medium grey edge markings for T-Max and Tri-X films. I get usable negatives but I get a feeling that the film is a little thin. When I develop using Diafine, I get a solid medium to dark grey edge marking. It makes a denser negative but not so dense as it appears to be overdeveloped.

Development process using T-Max:

Pour developer into film tank, which is then twist agitated for 4 to 5 rotations and every 30 seconds for 7 minutes and 30 seconds. I am using a 1+4 dilution factor at 68F.

Development process using Diafine:

Pour developer A into film tank, which is then twist agitated gently for 4 to 5 rotations and every 30 seconds for 3 minutes and 30 seconds. I then pour developer B into film tank, which is twist agitated gently for 4 to 5 rotations and every 30 seconds for 3 minutes and 30 seconds. I am using the solutions at 75F.


My thinking is that I should agitate the T-Max developer for 30 seconds when it start the development process. Does anyone have any thoughts on this matter? You input will be appreciated.

The markings on the edge of the film are exposed onto the film. Assuming the same edge exposure is used from roll to roll of the same film, then any difference in their tone is due to how much they are developed. So, it simply sounds like you are getting more development with Diafine than with T-max developer.

But the proof is in the printing -- make a print with the T-max developed film . Expose another roll of the same film using similar subject/light conditions and extend your development -- print with it and see if you like the denser negs. Over-all contrast should be higher for the denser roll, but check the mid-tones and see if you like them better than the thinner roll.

I believe the T-max instructions call for continous agitation for the first 30 seconds -- I have always assummed that it was to make sure that one got a good even start on the development...it will probably give you some extra density, but how much more, I do not know.

Vaughn

According to the developing instructions for T-max developer, you initially agitate for 5 seconds for small tanks (16 fld oz or less) and 30 seconds for larger tanks. I'll do the initial agitation for 30 seconds and see if this makes a difference.

I suspect that the edge markings vary considerably from batch to batch. Some of my bulk rolled Tri-X has darker edge markings than the factory loads when processed in the same developer. FP4+ from the bulk roll has almost indistinguishable edge markings, though the negatives are fine.

Your question is a little different. Remember that Diafine is a speed enhancing developer, and as such, it's not a stretch to think that it will develop the edge markings to a greater density than you'd get with normal development in TMax developer. Your agitation scheme with TMax developer is correct. Initial agitation should be continuous for the first 30 seconds with intermittent agitation for 5 seconds each 30 seconds. However, development times for Tri-X, TMax 400, and TMax100 are different. Kodak suggests the following times at 68 deg. F. in publication J-86 which you can download here: http://www.kodak.com/global/en/professional/support/techPubs/j86/j86.pdf

• Tri-X 400 (400TX) - 6 min
• TMX (TMax 100) - 7.5 min.
• TMY (TMax 400) - 7 min.

fschifano said:

I suspect that the edge markings vary considerably from batch to batch. Some of my bulk rolled Tri-X has darker edge markings than the factory loads when processed in the same developer. FP4+ from the bulk roll has almost indistinguishable edge markings, though the negatives are fine.

Your question is a little different. Remember that Diafine is a speed enhancing developer, and as such, it's not a stretch to think that it will develop the edge markings to a greater density than you'd get with normal development in TMax developer. Your agitation scheme with TMax developer is correct. Initial agitation should be continuous for the first 30 seconds with intermittent agitation for 5 seconds each 30 seconds. However, development times for Tri-X, TMax 400, and TMax100 are different. Kodak suggests the following times at 68 deg. F. in publication J-86 which you can download here: http://www.kodak.com/global/en/professional/support/techPubs/j86/j86.pdf

• Tri-X 400 (400TX) - 6 min
• TMX (TMax 100) - 7.5 min.
• TMY (TMax 400) - 7 min.

Click to expand...

This is useful material. I was relying on a handbook but I would imagine it's best to use current Kodak documentation. Also, I didn't realize that the edge markings varied with film batches. I've been using bulk film so it seems that the results I've been getting indicate that I've been processing correctly. I have been getting usable negatives from T-Max, however, it just that they seemed a little "thin" to my eye when compared to Diafine processed films.

Snapshot said:

...I would imagine it's best to use current Kodak documentation.

Click to expand...

Look around on the Kodak site for other technical documents as well. The tech pubs for their line of B&W films is the best in the business. Many of the questions that get asked here, would not be asked if some of the other manufacturers published data like that. Some of the data look intimidating at first, but with a little perseverance can be deciphered.

Actually, I've seen this on my film. I had "imported" and "USA" versions of the same film -- Kodak TMax 100, medium format 120 -- from B&H Photo. This was years ago, when the "imported" was made by a Kodak plant in England IIRC. The TMax made in England had very thin edge markings. The USA version was much darker.

Both films were developed in the same developer, same time, dilution, etc. Both printed perfectly. The densities were fine. The only differences were in the density of the edge markings.

Ya know that may be an interesting experiment to try and relate the density of the edge marking as an indication of proper negative densities. I wounder if anyone could just for the heck of it check to see if there is in fact any coorelation here?